Senate Republicans are now openly coordinating with the White House how the trial will be run (details here and here). It's sounding like they'll make it a rather rushed and prefunctory matter.
I've seen some Democrats and independents and never-Trump Republicans lamenting this but I don't agree. If the Senate is obviously conducting a sham trial, that will not fool anyone except Trump's base.
If they don't take the matter seriously, then I think that will badly hurt them in the 2020 elections. Public polls show a majority of Americans want Trump impeached and removed from office.
Ignoring that majority is very foolish because they're the ones who will decide the election in 2020. Pissing off the people you need may doom the GOP in 2020. Let's hope so.